Requirements for compact, efficient high power microwave generators have become more demanding as peripheral technical advances have forced the generators into applications which require higher power efficiency in a smaller volume. Diodes, each mounted at one extremity of each a plurality of coaxial lines, the plurality of lines being coupled to a combining cavity and sometimes to one or more stabilizing cavities are limited by the physical size of the combining cavity in terms of the number of coaxial lines which may be coupled thereto. Kurakawa's U.S. Pat. No. 3,628,171; the Harp et al, U.S. Pat. No. 3,931,587, and my U.S. Pat. No. 4,034,314, are typical of the prior art.
Hines U.S. Pat. No. 3,231,831, teaches the use of "Mode Control in Negative Resistance Devices." Kuno et al reveal "Push-Pull Operation of Transferred-Electron Oscillators," in Electronic Letters, Mar. 24, 1969, pp. 178, 179.